1. Field of the Invention
The present invention relates to audio processing techniques, and more particularly, to methods for controlling a power stage of a power amplifier and related apparatuses.
2. Description of the Prior Art
Digital power amplifiers, or so-called class-D power amplifiers, are commonly applied in audio processing devices due to their high efficiency. A digital audio power amplifier utilizes a pulse width modulation (PWM) circuit to generate a PWM signal for controlling the operation of its power stage according to an incoming digital signal.
Performance of the digital audio power amplifier relates to resolution (i.e. bit number) of the PWM circuit. In general, the performance of the digital audio power amplifier improves as the resolution of the PWM circuit increases. However, a conventional PWM circuit must operate at a higher frequency to raise the resolution. From the viewpoint of manufacturing, raising operation frequency means increasing production difficulty and cost. In consideration of production cost, the performance of the digital audio power amplifier is restricted by manufacturing limitations, and therefore the performance is difficult to be improved.